[V8] [Fwd: RE: [A8] steel bolt in aluminum]

[Kent McLean]

(Forwarded...)
-
Kent

-------- Original Message --------
Subject: RE: [V8] [A8] steel bolt in aluminum
Date: Sun, 27 Dec 2009 23:54:25 +0000
From: 7013885254 <chance9121 at gmail.com>
To: Kent McLean <kentmclean at comcast.net>

I highly doubt you would ever find an aluminum bolt in this applicaton.  There 
is a high load and shear stress on a blot in this area of any car, and aluminum 
would be a poor choice in this matter.  There are certain ypes of steel, 
particylarly types of stainless,  that are nonmagnetic as well.   This would be 
a plausible choice as well for a bolt that can't corrode and vind the suspension.

As for the bolt you've broken, its opossible that it suffered from a common 
issuse when dealing with dissimilar metals, if the sleave is not the same alloy 
as the bolt.  Either this or it was very firmly wedged in by its 'pinch' 
construction.

As well just a heads up, when removing pinch bolts from the factory you often 
must replace them with a bolt with an adjustable cam so an alignment shop can 
get the car within spec.  May want to check with an alignment shop or for an oe 
replacment part number.  Btw,  heat from a map gas torch often helps remove 
stubborn bolts,  followed by an impact hammer or sledge and punch.

Good luck.
---- Original Message ----
From: "Kent McLean" <kentmclean at comcast.net>
Date: 12/27/09 6:30 pm
To: "a8 at audifans.com" <a8 at audifans.com> ; "quattro" <quattro at audifans.com> ; 
"v8-list" <v8 at audifans.com>
Cc: "Rich, Jack" <Jack.Rich at kronos.com>
Subj: Re: [V8] [A8] steel bolt in aluminum
Rich, Jack wrote:
> I'm replacing my front axles, and the pinch bolt holding in the upper 
> control arms was a bear to get out on the passenger side.  The drivers 
> side is worse -- the head sheared off when I tried to spin it, and it 
> cannot be hammered out at all.  I'm going to have to drill it out.  
> But I can't help but notice that the bolt is magnetic, i.e. some sort 
> of steel, while the wheel bearing housing both looks like aluminum, 
> and is non-magnetic.
> 
> Do I have the correct bolt installed?  Is it supposed to be steel?

Jack,

I haven't seen much activity on the A8 list (this being the first posting I've
seen in a while), so I'm taking the liberty of forwarding it to the V8 list (as
I think they will have a vested interest as they move from their A8s) and the
main quattro list (because there are a lot of knowledgeable people there).

A quick glance at the Family Album doesn't help, as it doesn't seem to give the
materials of the items. For example, if I'm reading it right, Model A8Q, Year
1998 (you didn't say), MG 4, SG 07, Illustration 407-10, shows bolt 27 as Part
Number "N 101 312 03", "screw, hex. hd.", M10x105x32.

So, is it plausible to have a steel bolt in an aluminum casting? My guess would
be yes, as an aluminum bolt would have to be real thick. But that's just a guess.